Means for feeding ammunition belts to machine guns



Dec. 5, 1944. 2,364,309

MEANS FOR FEEDING AMMUNITION BELTS T70 MAcHIim GUNS J. D. NORTH Filed May- 12, 1942 A TTORNE Y Patented Dec. 5, 1944 MEANS FOR FEEDING AMMUNITION BELTS TO MACHINE GUNS John Dudley North, Wolverhampton, England, assignor to Boulton Paul Aircraft Limited, Wolverhampton, England, a British company Application May 12, 1942, Serial No. 442,714 In Great Britain August 26, 1939 4 Claims.

This invention relates to means for feeding ammunition belts to machine guns.

It is sometimes desirable to feed ammunition belts to a machine gun from a storage space or container located at some distance from the machine gun. For example it may be desired to feed ammunition belts to a machine gun mounted in a gun turret, from storage containers located outside the turret. In such cases the resistance to motion of the ammunition belt may be considerable with the result that the feed mechanism of the gun itself may be inadequate for effecting a satisfactory feed of ammunition to the gun so that either it is impossible to fire a burst from the gun or the gun is liable to frequent stoppages.

The object of the present invention is to provide improved means for smoothly feeding the ammunition belt to the gun, said means including a source of power additional to that provided by the gun itself, said additional source of power operating in the manner of a servomotor.

With the foregoing and other objects in view, as will hereinafter appear, the invention comprises the novel arrangement and combination of parts hereinafter described and claimed, it

being understood that changes in the particular embodiment of the invention, hereinafter described, may be made Within the scope of the claims without departing from the invention.

One embodiment of the invention is illustrated in the accompanying drawing in which:

Figure 1 is a diagrammatic view in perspective of the ammunition feeding mechanism and of a machine gun, and

Figure 2 is a view in vertical section of part of the apparatus illustrated in Figure 1.

Referring to the drawing, the feeder sprocket mounted on the shaft l consists of two sprocket discs 2 and 3, the teeth of which engage with the rounds 4 of the ammunition belt in the same way that an ordinary sprocket wheel engages with the rollers of a chain (see Fig. 2). The shaft l carries a spider 5 on which are mounted planet wheels 6 meshing with a driving sun wheel 1 on a shaft 8 driven through bevel gearing 9, It from a source of motive power such as an electric motor H. Planet wheels 6 also mesh with an internally toothed annulus 12. The annulus I2 constitutes the reaction member of the epicyclic gear and a brake band [3 is wrapped around the outer surface of the annulus which forms a braking surface. One end of the brake band I3 is anchored to a fixed point at Hi. When the annulus I2 is held against rotation by the brake band l3 the shaft I is driven from the shaft 8.

The ammunition belt 4 indicated by the broken lines in Fig. 1 is drawn up from below by the feeder sprocket and after leaving this sprocket it passes over an auxiliary idler roller l5 and then to the gun l6. As will be seen from the drawing, the belt is arched upwardly by the aux iliary roller I5 with the result that tension in the belt exerts a downward force on the auxiliary roller.

The roller [5 is mounted on arms 11 extending obliquely to the bisector of the angle made by the belt in passing over the roller I5. The arms are pivoted at 18 and are connected together by a bar [9 to which the free end of the brake band I3 is attached. It will be seen that the tension in the belt tends to swing the arms [1 clockwise, this tendency being resisted by springs 20. The clockwise swinging of the arms -l'l causes the brake band [3 to be tightened around the annulus l2 and therefore the braking effect of this band will vary in accordance with the tension in the ammunition belt.

When this tension is nil, that is to say when the gun is not firing, the braking effect on the annulus is nil and the annulus can rotate backwards with the result that no torque is transmitted to the feeder sprocket. As soon as the gun commences to fire, the tension in the ammunition belt is increased and the arms I! will be rocked clockwise in Fig. 1 to exert a braking effect on the annulus thus retarding the backward rotation thereof. A torque will thus be transmitted to the feeder sprocket to feed the ammunition belt towards the gun. If the rate of feed of the ammunition belt tends to become greater than is required by the gun, the tension in the ammunition belt will decrease thus permitting the arms I! to rock counter-clockwise in Fig. 1 to reduce the braking effect on the annulus. The speed of rotation of the feeder sprocket will thus be reduced accordingly. Similarly, if the tension in the ammunition belt increases due for example to a slight jamming of the ammunition belt in'guide tracks leading to the feeder sprocket or due to the gun consuming ammunition at a rate faster than it is fed forward by the feeder sprocket, the arms I! will be rocked clockwise to exert an increased braking efiect on the annulus and thus increase the speed of rotation of the feeder sprocket. Thus the tension in the ammunition belt will be maintained substantially constant and the ammunition will be fed smoothly to the gun, thus reducing any said axis and substantially on a level with the gun.

What I claim is:

1. Apparatus for feeding ammunition belts tomachine guns comprising a feeder sprocket the teeth of which engage the rounds ofthe ammunition belt to feed said belt towards the gun, a source of motive power for said feeder sprocket, a variable speed gear operatively connecting said source of motive power to said feeder sprocket, a member movable to control said variable speed gear and engaging the ammunition belt between .the feeder sprocket and the gun and means resiliently retaining said movable member in a position to hold the variable speed gear disengaged and to take up slack in the ammunition belt, said movable member being moved by increase in belt tension when the gun is fired, to engage the variable speed gear and to increase the speed of rotation of the feedersprocket with increase in belt tension.

2. Apparatus for feeding ammunition belts to machine guns comprising a feeder sprocket the teeth of which engage the rounds of the ammunition belt to feed said belt towards the gun, a motor for driving said feeder sprocket, a variable speed gear operatively connecting said motor to said feeder sprocket, a rockable control arm for said variable speed gear, a roller mounted on the end of said rockable control arm and engaging the ammunition beltbe'tween the feeder sprocket and the gun and means resiliently retaining said rockable control arm in a position to hold the variable speed gear disengaged and to take up slack in the ammunition belt, said rockable control arm being rocked by increase intehsion when the gun is fired, to engage the variable speed gear and to increase the speed of rotation of the feeder sprocket with increase'in belt tension.

3. Apparatus for feeding ammunition belts to machine guns comprising a feeder sprocket the teeth of which engage the rounds of the ammunition belt to feed said belt towards the gun,

' a source of motive power for said feeder sprocket,

up slack in the ammunition belt, said control member, being moved, by increase in belt tension when the gun is fired, to operate said brake whereby a torque is transmitted by the epicyclic gear to the feeder sprocket, the speed of rotation of said feeder sprocket varying with variations' in the tension of the ammunition belt.

4. Apparatus for feeding ammunition belts to machine guns comprising a feeder sprocket the teeth of which engage the rounds of the ammunition belt to feed said belt towards the gun,

a motor for driving said feeder sprocket, an

epicyclic variable speed gear operatively connecting said motor to said feeder sprocket, a braking surface rotatable with the reaction member of said, epicyclic gear, a rockable arm, a roller mounted on the end of said rockable arm and engaging the ammunition belt betweenthe feeder sprocket and the gun, a brake band co-operating with said braking surface, one end of said brake band being attached tov said arm 'and the other end to a fixed anchorage, means resiliently 're- I the brake band on the braking surface so that a torque is transmitted to the feeder sprocket and the speed of rotation of the feeder sprocketis varied with variations in tension of the ammunition belt.

JOHN D. NORTH. 

